Image reading apparatus for automatically setting up image reading region and method thereof

Abstract

An apparatus and a method of reading an image wherein processing conditions can be set up based on image data obtained by scanning image information recorded on an original to be read. The entire image reading region of a reading device with the original held therein is scanned to produce scanned data including the image data. A separator circuit compares the scanned data with given threshold data to separate the scanned data into first scanned data from the original and second scanned data from portions other than the original. An adder adds together either the number of pixels read from the first scanned data or the number of pixels read from the second scanned data along a main scanning direction for each given pitch extending in an auxiliary scanning direction, whereas another adder adds together either the number of pixels from the first scanned data or the number of pixels from the second scanned data along the main scanning direction for each given pitch extending in the main scanning direction. Each of first and second region setting-up circuits compares, for each given pitch, the number of the pixels added together along each of the main and auxiliary scanning directions with a given number of threshold pixels so as to determine an image reading region of the original, which extends in each of the main and auxiliary scanning directions.

What is claimed is: 
     
       1. An image reading apparatus for setting up processing conditions based on image data obtained by scanning image information recorded on an original to be read, said image reading apparatus comprising: a reading unit for scanning the entire image reading region of a reading device with the original held therein so as to read scanned data including the image data;   a separating circuit for comparing said scanned data with given threshold data so as to separate said scanned data into first scanned data read from the original and second scanned data read from portions other than the original;   a first adding circuit for adding together either the number of pixels read from said first scanned data of said scanned data separated into said first and second scanned data or the number of pixels read from said second scanned data thereof along a main scanning direction for each given pitch extending in an auxiliary scanning direction;   a first region setting-up circuit for comparing, for each said given pitch, the number of the pixels added together along the main scanning direction with a predetermined number of threshold pixels so as to determine an image reading region of the original, which extends in the auxiliary scanning direction;   a second adding circuit for adding together either the number of pixels read from said first scanned data or the number of pixels read from said second scanned data along the auxiliary scanning direction for each given pitch extending in the main scanning direction; and   a second region setting-up circuit for comparing, for each said given pitch, the number of the pixels added together along the auxiliary scanning direction with the predetermined number of the threshold pixels so as to determine an image reading region of the original, which extends in the main scanning direction;   whereby given processing conditions are set up based on image data set in an image reading region determined by said image reading region of the original extending in the auxiliary scanning direction and said image reading region of the original extending in the main scanning direction.   
     
     
       2. An image reading apparatus according to claim 1, wherein said first and/or second region setting-up circuit includes a region selecting circuit for selecting an image reading region having a maximum width as either said image reading region of the original extending in the auxiliary scanning direction or said image reading region of the original extending in the main scanning direction when either said image reading region defined by comparing the number of the pixels added together along the main scanning direction with the predetermined number of the pixels or said region defined by comparing the number of the pixels added together along the auxiliary scanning direction with the predetermined number of the pixels is formed as a plural region. 
     
     
       3. An image reading apparatus according to claim 1, wherein said reading unit comprises a light source for applying illuminating light to the original, an auxiliary scanning drive mechanism for displacing the original in the auxiliary scanning direction, a focusing lens for focusing either transmitted one of the illuminating light applied to the original or light reflected from the original, and a plurality of photoelectric converter elements for reading image information on the original produced by focusing either said transmitted one or said reflected light with said focusing lens. 
     
     
       4. A method of reading an image wherein processing conditions are set up based on image data obtained by scanning image information recorded on an original to be read, said method comprising the following steps: a first step of scanning the entire image reading region of a reading device with the original held therein so as to read scanned data including the image data;   a second step of comparing said scanned data with given threshold data so as to separate said scanned data into first scanned data read from the original and second scanned data read from portions other than the original;   a third step of adding together either the number of pixels read from said first scanned data of said scanned data separated into said first and second scanned data or the number of pixels read from said second scanned data thereof along a main scanning direction for each given pitch extending in an auxiliary scanning direction;   a fourth step of comparing, for each said given pitch, the number of the pixels added together along the main scanning direction with a predetermined number of threshold pixels so as to determine an image reading region of the original, which extends in the auxiliary scanning direction;   a fifth step of adding together either the number of pixels read from said first scanned data or the number of pixels read from said second scanned data along the auxiliary scanning direction for each given pitch extending in the main scanning direction;   a sixth step of comparing, for each said given pitch, the number of the pixels added together along the auxiliary scanning direction with the predetermined number of the threshold pixels so as to determine an image reading region of the original, which extends in the main scanning direction; and   a seventh step of setting up given processing conditions based on image data set in an image reading region determined by said image reading region of the original extending in the auxiliary scanning direction and said image reading region of the original extending in the main scanning direction.   
     
     
       5. A method according to claim 4, wherein said given processing conditions in said seventh step comprise scanning conditions and image processing conditions, said scanning conditions being composed of selection of an image reading region on the original, reading magnification, turning angle at the time of reading of the original, the type of halftone at the time of the halftone scanning, the number of lines on the screen, and color plates in an original film plate; and a judgment made as to whether borders (edges) with respect to the original film plate have been set up; a judgment made as to whether resist marks have been applied; and a judgment made as to whether an exposure condition at the time of the color separation of the original has been set up, and said image processing conditions being composed of set-ups of the densities of highlights and shadows, dot percent, gradation, color correction and sharpness; and undercolor removal or the like with respect to the original film plate.